Lens grinding machine



Jan. 27, 1942. R. E. FOSDICK LENS GRINDING MACHINE Filed Aug. 25, 1938 3Sheets-Sheet 1 INVENTOR 205527 E FOSQLCK.

BY A

Q an R mu ATTORN EYS s Sheets-Sheet 2 Filed Aug. 25, 1938 INVENTOR EIZT.F'OSD K ATTORNEYS Jan; 27, 1942. R. E. FOSDICK LENS GRINDING MACHINEFiled Aug. 23, 1958 3 Sheets-Sheet 3 INVENTOR 7 eoamr Ef'OJD/CK W [W H Ll l lu ATTORNEYS Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE-LENS GRINDING MACHINE Robert E. Fosdick, Dayton, Ohio Application August23, 1938, Serial No. 226,354 6 Claims. (01. 51-67) This inventionappertains tothe art of grinding lenses and more particularly to theprovision of an automatic machine for this purpose having provision forvarious types of adjustmentwhereby any desired sort of lens grindingoperation may be accomplished with facility, accuracy and while anabrasive block is held thereagainst and,

moved backward and, forward over the surface to be ground. This is anoperation requiring great skill of an operator so engaged, involving thefactors of speed of rotation of the lens glass, the pressure with whichthe abrasive is held thereagainst, the speed of reciprocating movementof the abrasive across the surface to be ground, and the uniformity ofthis reciprocating movement. In the hand operation of lens grinding theresults of these factors are dependent entirely upon the skill of theoperator, and under most favorable conditions accuracy and miiformity ofresults is an object most difficult to achieve.

It is, therefore, an object of the present invention to secure thesedesired results by the provision of a machine in which the human elementcontrolling the factors above mentioned is to a great extent eliminated,and by means of which uniform results are obtained automatically inaccordance with certain initialadjustments It is a further object of theinvention to provide a machine of the type set forth having provisionfor a variety of adjustments whereby to enable the same to perform anydesired lens grinding operation.

A still further object of the invention is to provide a machine whichwill duplicate any hand operation. of lens grinding but with greateraccuracy and uniformity than heretofore possible.

While it is impossible, of course, to eliminate entirely the humanelement, or requisiteskill of an operator to perform, satisfactorily,special lens grinding operations, such as those for which the presentinvention has been designed, it isthe aim and actual accomplishment ofthe instant invention to confine the need for such skill to initialadjustments of the operating parts of the machine, which then performsuniformly and accurately in accordance therewith. Once initialadjustments are made, the skill of the operator is mainly relied upon todetermine the extent to required, and, of course, the ability of anoperato to make proper adjustments is essential.

In carrying out the practice of the invention '1 providea machinecomprising means for revolvin accordance with a variety of adjustmentsof adjustable ,means provided for this purpose, means forreciprocatingthe abrasive holding deviceacross the surface of the lensglass, means for adjusting the length of stroke of the reciprocatingmeans, and'means for reciprocating the same atdifierent rates of speed.The various motions for accomplishing the above. objects and purposesare produced from a single source of power.

' Other objects, advantages and features .of novelty will appear morefully as the description of the invention progresses in' conjunctionwith the drawings and as defined in the appended claims. In thedrawings: ,I Y I Figure 1 is a top plan view of the reciprocating meansand ancillary parts.

Figure 2 is an end elevation looking in the direction of the arrows 2-2of Figure 1. j

speed, means for holding an abrasive substance at varying degrees ofpressure against the lens glass Figure 3 is a side viewof a portion of amachine embodying the invention, the same Particularly-showing therelation of parts which hold and act upon the lens glass to be ground,and their relation to their respective operating instrumentalities. r v

I Figure-4 is a view contiguous to Figure 3, being a side view of aportion of the machine illustratedin Figure 3, showing more particularlythe operating instrumentalities.

Figurev 5'is an end view of the machine illustrated in the foregoingfigures, illustrating the relation of the instrumentalities shown inFigure 4.

Referring now to the-embodiment of the invention shown in theaccompanying drawings, the same generally comprises a frame A, theupperportion of which forms a table B upon which is supported a carrierbracket C to which isadjustably secured a reciprocating arm D carryingan abrasive block E. In the lower part of the frame is'mounted a sourceof power F which, through instrumentalities later to be described,drives the eccentric shaft G, for reciprocating. the arm D, and the mainspindle H towhich latter is splined the lens block or carrier I.

Figures 3 and 4 are contiguous, the former showing the instrumentalitiespositioned above the table B and the latter showing thoseinstrumentalities positioned below the table B;

Structure For the present Figures 4 and 5 will be more particularlyreferred'to. I

'Themotor F is carried by a bracket l suitably secured to base Z'of theframe A, and to its drive shaft 3 is fixed a pulley 4. A belt 5,'trainedover pulley l' and a second pulley 6 fixed to the main drive shaft 1,enables said shaft 1 to be driven by the motor. Theshaft is journaled inbearings 8 and 9 carried by brackets l0 and II respective- 1y which aresecured to upright members l2 and |3 respectively of the frame A.

Fixed to the drive shaft 1 is a step-pulley l4. A belt I5 is trainedthereover and also over a step-pulley Hi, the latter being fixed to adriven shaft I! by means of a key l8 engaging the key-way H] of saidshaft Shaft IT is journaled in bearing cross-members 20 and 2|. securedto the base 2 of frame A and also extends through passages 22 and 23 ofa slide member K. Shaft also carries at one end a roller 24 which is indriving engagement with the friction disc 25 fixed to the main spindleH.

The slide member K is movable from left to right, referring to Figure 4,in a guide-way 2'! carried by a bracket 28 bolted to the base 2 of frameA. Said slide member K has an internally threaded passage 29 whichreceives the threaded end 39 of screw shaft 3| rotatably journaled in abearing cross member 32 secured to upright member I3 of frame A. Saidscrew shaft 3| is prevented from horizontal movement by a collar 33fixed thereto which is positioned against said bearing 32. Exteriorly ofthe frame A there is secured to said screw shaft 3| an operating wheelor member 34.

The speed at which the main spindle H is rotated is regulated byoperation of the screw shaft 3| rotated by the wheel 34. Rotation of thescrew shaft 3| causes leftward or rightward movement, referring toFigure 4, of the slide member K by cooperation of the internallythreaded passage 29 thereof with the threaded portion 39 of said screwshaft 3|. Movement of slide member K is transmitted to the driven shaftI! by engagement of said member with abutment member Ha fixed to shaftI! or by engagement with the roller 24, depending upon the direction inwhich said slide member K is moved, to move said shaft correspondingly.The roller 24 is thus caused to engage the friction disc at a greater orless distance from the center thereof to vary the speed of rotation ofsaid disc, and consequently, of said main spindle H. The rotationalspeed of said spindle H is also controlled by selecting the portions ofthe step pulleys l4 and I6 over which the belt I5 is trained, as will beapparent.

Also fixed to drive shaft 1 is a pulley 35. Over this pulley and alarger pulley 35 is trained belt 31, the pulley 36 being fixed to adriven shaft 38. A step-pulley 39 is fixed to this latter shaft andtrained thereover and also over a step-pulley 40, fixed to a drivenshaft 4| is a belt 42. The shaft 4| is journaled in bearingcross-members 43 and 44 secured to the table or platform B. Pulley 49 isfixed to shaft 4| by a key 45 slidable in a keyway 46. Thus shaft 4| ismovable through the bearings 43 and 44 in the same manner that shaft His movable through its respective supporting bearings.

Shaft 4| extends through passages 41 and 48 of a slide member L and hassecured to one end the roller 49 in driving engagement with a frictiondisc 50 secured to the eccentric shaft G. The slide member L is slidablefrom left to right, referring to Figure 4, in a guide-way 5| secured tothe underside of the table B. Said slide member ,L has an internallythreaded passage 52 through which extends the threaded portion 53 of ascrew shaft 54 journaled in abearing 55 secured to upright member |3 ofthe frame A. Said shaft 54 is maintained against horizontal movementwith respect to bearing 55 by a collar 55 fixed to the shaft and whichengages said bear- Driven shaft 4| is movable leftwardly or rightwardly,referring to Figure 4, upon operation of the hand wheel 51 fixed toscrew shaft 54, to cause engagement of roller 49 closer to or fartheraway from the center of disc 50, by engage ment of slide member L withabutment member 58 on shaft 4|, or roller 49, in the same manner as thatdescribed in reference to the movement of shaft IT. The speed ofrotation of eccentric shaft G is thus controlled as a consequencethereof, as well as by adjustment of belt 42 upon the step-pulleys 39and 40.

Now referring more particularly to Figures 1 to 3 it will be seen thatthere is supported at the top of eccentric shaft G an eccentric disc orplate M fixed thereto as by the set-screw 59. Formed on the upper sidethereof is a guide-way 60 in which is slidably mounted the slide member5| which is adapted to be fixed at any desired adjustment in the lengthof the guide-way by one or more of the set screws 62a, 62b, or 620. Apivot bolt 63 extends through the slidable member 6| and one end of apitman 64, the other end of the latter being pivotally secured to aslidable plate 65 as by a pivot bolt 66 extending therethrough. Theplate 65 is slidable from left to right, referring to Figures 1 and 3,in the grooved ways or channels 61 and 68 of the carrier member orbracket C, the latter being suitably secured to the upper side of thetable B as by bolts or otherwise.

Fastened to the slidable plate 65 is a U-shaped bracket N between theupstanding portions 69 and 10 of which one end of the reciprocating armD is adjustably secured as by a pin extending through a hole in said armand through one of the pairs of oppositely disposed holes 12a, 12b or 20in the upstanding portions 69 and 10 of the U-shaped bracket N. Anadjusting screw 13 has a threaded portion 13a extending verticallythrough the arm D at a point between the ends thereof and engages theplate 65 to support the said arm at such point.

Also extending vertically through said arm D is a carrier pin 14 formedwith a lower rounded or ball end 14a which is received in a ball socketof the abrasive block E. The pin 14 may be fixed permanently respectingthe arm D or adjustably received in one of the openings 15a, 15b, 15c,15d,

or c, its vertical position respecting said arm grinding operation bycontact of said block with the lens to be ground.

Arm D is reciprocated through rotation of cocentric plate "M to which ispivotally connected the pitman 64 as above described, said pitman beingfree to move longitudinally and transversely in the under-cut portion11'of the carrier C beneath the plate 65. The length of stroke'of arm Dis regulated by adjusting the position of the slidable member Elradially respecting the eccentric plate M, by'the means above described.

The lens block or carrier I has formed therebeneath a hub 18 whichreceives the upper end 79 of the main spindle H, said end 19 beingsplined to said hub, To the carrier I is suitably secured a lens 89 tobe ground.

r 1 Operation The block of glass 80' which is to be ground into a lenshaving been suitably secured to the carrier I, ordinarily by cementingthe same thereto, and an abrasive block E of the desired curvaturehaving been. secured to the arm D, the proper tension of the block Eupon the glass 80v is adjusted by securing the arm D to thebracket N inthe desired vertical position and regulating the adjusting screw 13 withreference to the plate 65. The length of stroke of the arm D is adjustedby releasing the set screws 52a, 62b, and and moving slide member 61radially inward or outward with respect to the center of the eccentricM.

Next the belts l5 and 42 are trained over the desired steps of thepulleys I4 and I6, and 39 and 40, respectively. The hand wheels 34 and5'! are then operated to position the rollers 24 and 49, respectively,at the proper distance" from the center of their friction discs 25 and50. This manipulation will regulate the speed of rotation of the mainspindle H and eccentric shaft G respectively.

Now the motor F is started into operation rotating motor shaft 3 andshaft 1 through'belt' 5 trained over pulleys 4 and 6. Shaft [-1 will beconsequently rotated through belt 15 trained over step-pulley I4 and 16.Main spindle H will be rotated by engagement of roller 24, fixed toshaft IT, with friction disc 25. Shaft 38 will be rotated by belt 31trained over pulleys 35 and 36, and shaft 4| will be rotated throughbelt 42 trained over step-pulleys 39and 40. The eccentric shaft G willthus be rotated by engagement of roller 49, fixed to shaft 4|, withfriction disc 50. Rotation of the eccentric plate M, fixed to shaft Gwill reciprocate the pitman 54, and consequently plate to which it ispivotally attached, bracket N secured to said plate, and arm D, attachedto said bracket. This will cause abrasive block E to move across thesurface of the glass 86 to grind the same. I

The tension with which the abrasive block E is held against the glasswill be adjusted by turning the adjusting screw 13 to move the arm Dcloser to or farther away from the plate 65. As the grinding operationproceeds the ground glass dust and abrasive dust will be caught in thepan or tub 8| supported on the table B and surrounding the portion ofthe main spindle H protruding above the top of said table.

During the grinding operation hand wheels 34 and 51 may be actuated tovary the rotational speeds of the main spindle H and the eccentric shaftG, respectively, the latter affecting the speed of reciprocation of thearm D.

From the above it will be seen my invention provides an automatic lensgrinding machine suitable for the performance of many sorts of lensgrinding operations as a result of the many adjustments of the variousinstrumentalities provided,

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In a device of the class described, in combination, a frame, arotatable member, a re- Jail ciprocable member, one of said memberscarrying an abrasive material, the other of said memfor reciprocatingsaidcarriage respecting said first member in a straightline path, andmeans for vertically adjusting said arm to different fixed positionsrelative to said carriage while maintaining said arm in a horizontalposition.

2. In a device of the class describednin combination, a frame, arotatable member, a reciprocable member, one of said members carrying anabrasive material, the other of said members being adapted to carry aglass blank to be ground, means for rotating the first member, acarriage slidable in said frame, an arm pivotally secured to saidcarriage and supporting the second member proximate the first member,means associated with said carriage for reciprocating the same in astraight line path, means for vertically adjusting said arm to differentfixed positions respecting said carriage, and means for verticallyadjusting said second member relative to said arm.

3. In a device' of the class described, in combination, a frame, arotatable member, a reciprocable member, one of said members carrying anabrasive material, theother of said members being adapted to carry aglass blank to be ground, means for rotating the first member, acarriage slidable in said frame, an armpivotally secured to saidcarriage and supporting the second member proximate the first member,means associated with said carriage for reciprocating the same in astraight line path, means forvertically adjusting said arm to differentfixed positions respecting said carriage, means for vertically adjustingsaid second memberv relative to said arm, and means for adjusting theangle of said arm relative to said carriage.

4. In a device of the class described, in combination, a'.frame, arotatable member, a reciproc'able member, one of said members carryingan abrasive material and the other of said members being adapted tocarry a glass blank to be ground, means for rotating the first member, acarriage slidable in said frame and supporting the second memberproximate the first,

and means for reciprocably sliding said carriage in said framerespecting said first member, driving means common to both'the aforesaidmeans and including instrumentalities interrelating the same forsimultaneously varying the relative speeds of one to the other, andseparate means .associated with each of said first and second means forindependently varying the speed of each.

5. In a device of the class described, in combination, a frame, arotatable member, a spindle associated therewith, a reciprocable member,one

of said members carrying an abrasive material and the other of saidmembers being adapted to carry a glass blank to be ground, means forrotating the first member, a carriage slidable in said frame andsupporting the second member proximate the first, means for reciprocablysliding said carriage in said frame respecting the first member, drivingmeans common to both the aforesaid means and comprising a pair ofrotatable spindles each of which is associated with one of said means, afriction member fixed to each of said spindles, a plurality of shaftsslidable in said frame, each shaft having means engageable with one ofsaid friction members, said driving means comprising instrumentalitiesfor varying the rotative speeds of said shafts relative to each other,and means associated with said shafts for axially shifting the sameradially respecting said friction members to vary the rotational speedof 'either' of said spindles independently of the other.

6. In a device of the class described, in combination, a frame, arotatable member, a reciprocable member, one of said members carrying anabrasive material and the other of said members being adapted to carry aglass blank to be ground, means for rotating the first member, acarriage slidable in said frame and supporting the second memberproximate the first, means for reciprocably sliding said carriage insaid frame respecting the first member, driving means common to both theaforesaid means and comprising a pair oi'rotatable spindles each 01which is associated with one of said means, ec-

centric means associated with one of said spin-v dles and said carriagefor reciprocating the latter, means associated with each of saidspindies for varying the rotative speed thereof independently of therotative speed of the other, said driving means includinginstrumentalities interrelating said spindles for simultaneously l0varying the relative rotative speed of each to the other.

ROBERT E. FOSDICK.

